“The most effective way to combat whooping cough is to vaccinate pregnant women”

This is an alarming record for Public Health France: more than 130,000 cases of whooping cough recorded since the start of 2024, with 35 deaths, including 22 children. The majority of infants who died were less than one year old.

The Pasteur Institute is talking about a record epidemic, the strongest in twenty-five years. “In almost fifteen years that I have been doing pediatrics, I have never seen such an intense epidemic”confirms Romain Basmaci, head of the pediatrics-emergency department at the Louis-Mourier hospital in Colombes (APHP) and secretary general of the French Pediatric Society.

He also warns: “We are not yet out of the epidemic phase. » After the start of the epidemic observed at the end of last year and a “big peak in spring”whooping cough started again in September.

Overall immunity less “stimulated”

Explanations for this resurgence “are complex”cautiously specifies the pediatrician. But the first hypothesis is based on weakened overall immunity, due to the Covid-19 pandemic. “Pertussis epidemics are cyclical, like many infectious pathologies. The last one took place around 2012. The epidemic should have returned in the years 2019-2020 but because of Covid, nothing happened: everyone was masked, there were barrier measures everywhere. » The epidemic was therefore “shifted”and its late reappearance, after the lifting of barrier measures, can explain a stronger rebound.

This less “stimulated” immunity because of Covid is an avenue cited by researchers from the Pasteur Institute and Public Health France. “One of the concerns with the whooping cough vaccine is that it maintains short-term immunity, for five to ten years maximum”abonde Romain Basmaci.

One thing is certain according to him: the explosion of whooping cough is not linked to a drop in vaccination coverage. In France, coverage is 96.7% for first injections, 98.6% for boosters, according to Health Insurance.

“Not aberrant” to make “tetravalent vaccines”

So, how can we strengthen the protection of the population, and in this case the youngest, who are most exposed to serious forms of whooping cough? Adults should be reminded of the diphtheria, tetanus, poliomyelitis (DTP) trio at ages 25, 45 and 65. Which does not include whooping cough. But boosters are recommended for young parents, grandparents and early childhood and health professionals, in regular contact with babies.

“We can also benefit from these reminders (DTP) to give whooping cough boosters, if necessary,” adds the pediatrician. “In the current epidemic period, it does not seem aberrant to offer tetravalents (which cover four diseases). »

The top priority for pediatricians remains to vaccinate pregnant women. A recent recommendation (April 2022), explaining still low coverage of this population. “But this is what remains the most effective », insiste Romain Basmaci.

For a simple reason: a vaccine during pregnancy allows a “antibody peak passes into the placenta”. “The child will therefore be able to receive these antibodies. They will protect him for four to six months, the time to give him his vaccines and for him to replace the maternal antibodies with his own antibodies, which he will produce following vaccination.explains the pediatrician.

An infection that can be fatal for babies

For loved ones, the best thing to do, in addition to vaccination, is not to approach babies if they are sick. Because whooping cough is extremely contagious. The famous R0, the reproduction rate of the virus, is ten to fifteen cases. In other words, one affected person can infect fifteen additional people. For comparison, the R0 of Covid-19 is two to three cases.

The classic symptoms are above all “prolonged coughing fits, without resumption of breathing between episodes”, explains Romain Basmaci, miming an uninterrupted cough on the phone. “At the end, there is a noisy inspiratory recovery which we call “cock crow”, hence the name whooping cough. »

In babies, severe forms can be fatal: “slowing of heart rate, even respiratory arrest, discomfort with loss of consciousness, and possible neurological disorders in cases of so-called malignant whooping cough”lists the pediatrician.

Whooping cough is therefore far from harmless. “You should know that the babies we receive can stay hospitalized for more than a month. This is not a small infection that will go away in three days. »

Margaux Malinge